Nozzle assembly for applying a liquid to a substrate

ABSTRACT

The aim of the invention is to achieve a rapid, homogeneous application of a liquid with as little force as possible to a substrate. To achieve this, the invention provides a nozzle assembly ( 22 ) for applying a liquid to a substrate, said assembly having a nozzle body ( 26 ) comprising a plurality of nozzles ( 36 ) that are substantially arranged in a line and a guide plate ( 28 ) that extends essentially in a vertical direction with a straight lower edge. According to the invention, the nozzles ( 36 ) above the lower edge are directed towards the guide plate ( 28 ) in such a way that a film of liquid forms on the guide plate ( 28 ) and flows over the lower edge ( 64 ).

BACKGROUND OF THE INVENTION

The present invention relates to a nozzle assembly for applying a liquidto a substrate.

In many fields of application, especially those for producing wafers andmasks during the treatment of a substrate, it is necessary to deposit alayer of liquid such as a developer for example, on the wafer or themask.

In the past, this has been done using a single nozzle which was directedtowards the substrate and was swept or scanned over the mask or thewafer in raster-like manner in order to wet the entire surface of thesubstrate. As an alternative, consideration has also been given to theuse of several mutually adjacent nozzles which were directed towards thesurface of the substrate and wetted the entire substrate in the courseof a single sweep.

If the liquid being applied is, for example, a liquid developer which isused for the development steps in a micro-lithographic process, it isimportant for the quality of the final product to ensure that the sameprocess progress is reached—i.e. that there is a uniform degree ofdevelopment—over each sub-area of the surface of the substrate beingtreated. The rate at which the process progresses is basicallydetermined by the quantity of developer applied, the dwell time on thesubstrate and the mechanical force with which the liquid is applied tothe surface of the substrate. Consequently, it is necessary for thedeveloper to be applied simultaneously over the entire surface of thesubstrate in as force-free and homogeneous a manner as possible in orderto ensure that the process progresses at as homogeneous a rate aspossible.

In order to ensure that the liquid is applied as simultaneously aspossible when applying it through a single nozzle, the nozzle shouldhave a very high scanning speed, and a very high flow speed for themedium should be selected since large temporal inhomogeneities in theapplication of the medium would otherwise arise. However, the high speedof flow leads to a large mechanical deposition force during theapplication of the medium, this being something which should be avoided.Moreover, when using a single nozzle, a pattern corresponding to thepattern of the nozzle develops on the surface of the substrate becausethe medium is not usually applied evenly over the width of the areabeing supplied by the nozzle—both in regard to the force of applicationand the quantity of liquid applied.

When using a plurality of mutually adjacent nozzles, the applicationtime can be substantially reduced as compared with a single nozzle,whereby the temporal inhomogeneity can be reduced when the medium isapplied in this manner. However, it is still necessary to use highspeeds of flow in order to enable the medium to be applied assimultaneously as possible, this thereby again resulting in a largemechanical deposition force during the application of the medium.Moreover, the development of a pattern described above still occurs forthe individual nozzles.

Furthermore, a slot nozzle for applying a liquid high-polymer materialis known from EP 03 66 962 A2. The slot nozzle consists of a two-piecenozzle body, whereby a first part incorporates a feed channel andseveral stop valves which are able to open and close a connectionbetween the feed channel and corresponding outlet bores in the firstpart. Each of the outlet bores extends towards the second part of thenozzle body and is directed towards an elongated spreading chamber whichis in the form of a recess in the second part. An outlet slot is formedbetween the two parts below the spreading chamber.

Based upon the above state of the art, the object of the presentinvention is to provide a device which enables rapid, homogeneousapplication of a liquid to a substrate in as force-free a manner aspossible.

SUMMARY OF THE INVENTION

In accordance with the invention, this object is achieved in the case ofa nozzle assembly for applying a liquid to a substrate in that thenozzle assembly comprises a nozzle body incorporating a plurality ofnozzles located substantially in a line and a substantially verticallyextending deflection or guide plate having a flat surface and a straightlower edge, wherein the nozzles are directed towards the flat surface ofthe guide plate above the lower edge so that a liquid film forms on theguide plate and flows off over the lower edge. In the case of a deviceconstructed in this manner, a substantially homogeneous liquid film canbe formed on the guide plate, and can be applied as a homogeneous filmto the substrate which is to be wetted. Furthermore, the film can beapplied to the surface of the substrate with a uniform force ofapplication since the development of a pattern produced by individualnozzles no longer occurs on the surface of the substrate. Moreover, theliquid film can be applied quickly by means of a single relativemovement between the substrate and the device. Although high liquid flowspeeds must also be used here, the component of force effective on thesurface of the substrate does not thereby increase, or at least, notsubstantially so. The mechanical force of application is substantiallyindependent of the speed of flow through the nozzles and is essentiallydetermined by the flow path over the guide plate and the height of thedrop between the lower edge of the guide plate and the surface of thesubstrate.

In a particularly preferred embodiment of the invention, a downwardlywidening gap is formed between the nozzle body and the guide plate, thisthereby assisting the formation of a homogeneous liquid film on theguide plate in a direction towards the lower edge. In order to simplifythe construction of the gap, the latter is preferably formed by a flatsurface of the nozzle body and a flat surface of the guide plate whichform an acute angle therebetween.

In order to enable the device to be used for various liquids havingdiffering viscosities, the angle is preferably adjustable. The formationof a homogeneous liquid film in dependence on the liquid can thereby beachieved. The angle is preferably between 0.5° and 4°. Good results canalso be achieved, in particular, in an angular range of between 1° and3°, or between 1.5° and 2.5°.

In one embodiment of the invention, the flat surface of the guide plateextends downwardly over the entire flat surface of the nozzle body. Itis thereby ensured that the liquid film will peel-off cleanly from thelower edge of the guide plate and that this break-away process will notbe affected by the nozzle body.

In order to simplify the construction of the device, the guide plate isattached directly to the nozzle body. In particular, this therebyenables the guide plate and the nozzle body to be moved as a unit.Hereby, the guide plate is preferably attached to the nozzle body abovethe nozzles in order to avoid having attachment elements in the spacebelow the nozzles which could affect the homogeneity of the liquid filmon the guide plate.

In order to prevent the liquid issuing from the nozzles moving upwardlybetween the guide plate and the nozzle body and thus possibly impairingthe homogeneity of the liquid film, provision is preferably made for aseal to be located above the nozzles between the nozzle body and theguide plate. Preferably, a recess is provided in the nozzle body, saidrecess having a complementary shape to that of the seal. A securearrangement and adequate retention of the seal are thereby ensured.Preferably, the seal has a round cross section.

In accordance with a particularly preferred embodiment of the invention,the nozzles are formed by straight passages in the nozzle body, whereby,in terms of height, the inlet ends of the passages lie below the outletends thereof. This arrangement thus prevents liquid from dripping fromthe nozzles and thereby producing bubbles in the liquid system when thedevice is not in operation i.e. when there is no flow of liquid. Suchbubbles would adversely affect the process of continuously andcompletely wetting the surface of the substrate. Preferably, the inletends of the nozzles flow into a common distributor line which has asubstantially larger cross section than the respective nozzles. Asubstantially uniform speed of flow through all the nozzles is therebyensured.

In order to prevent a build-up of fluid pressure on the nozzles when thesystem is switched-off which could lead to an outflow of liquid, theinlet ends of the nozzles are located at or in the proximity of thehighest point of the distributor line.

In order to produce as homogeneous a pressure distribution as possiblewithin the distributor line, provision is preferably made in a preferredembodiment of the invention for a supply line to lie below thedistributor line and be connected to the distributor line by a pluralityof feeder lines. The provision of the plurality of feeder lines enablesa homogeneous pressure distribution to be obtained within thedistributor line and thus a homogeneous distribution of pressure overall the nozzles. Due to the fact that the supply line lies below thedistributor line, it is also ensured that no pressure will be exerted onthe liquid in the nozzles when the system is switched off. Moreover, theconstruction of the liquid system consisting of the supply line, thedistributor line and the inclined nozzles enables air to beautomatically evacuated from the system when it is being filled againstthe force of gravity. Moreover, the emergence of liquid from the nozzlescan only be effected against the effect of the force of gravity and isthus virtually impossible. A homogeneous liquid film can thereby beproduced again immediately after a restart when the liquid system hasbeen switched off for a long period of time because the liquid system isalways uniformly filled with liquid and bubbles cannot occur therein.

For the purposes of obtaining a uniform distribution of pressure withinthe distributor line, the feeder lines between the supply line and thedistributor line are preferably evenly spaced over the entire length ofthe distributor line.

In order to assist the homogeneous formation of the liquid film on theguide plate, at least the surface of the guide plate directed toward thenozzles is preferably made of a hydrophilic material.

In order to enable complete wetting of the surface of a substrate, amechanism for producing a relative movement between the substrate andthe guide plate is preferably provided. Hereby, the mechanism preferablycomprises a unit for moving the guide plate substantially parallel tothe surface of the substrate so as to provide a uniform mechanical forceof application over the entire substrate.

In one embodiment of the invention, the mechanism is a linear-movementunit for moving the substrate and/or the nozzle body with the guideplate. In an alternative embodiment, the nozzle body and the guide plateare attached to a pivotal arm, whereby the maximum possible pivotalradius is selected in order to prevent the occurrence of inhomogeneitiesdue to the pivotal movement.

In order to ensure adequate and uniform wetting of the substrate, theguide plate is preferably wider than the substrate. This is ofparticular advantage since the liquid film comprises inhomogeneities inthe boundary regions of the guide plate.

In order to form a homogeneous liquid film corresponding to the width ofthe substrate, the outermost nozzles in the nozzle body are preferablyspaced by a distance which is greater than the width of the substrate.

In a preferred embodiment of the invention, a mechanism is provided foradjusting the spacing between the lower edge of the guide plate and thesubstrate. The head or height of fall of the liquid film can thereby bechanged in order to adjust the force with which the liquid is applied tothe substrate. In a further embodiment of the invention, the lower edgeof the guide plate is a sharp edge in order to provide a definedbreak-away edge at the lower edge of the guide plate. This therebyensures that the liquid film will run-off in a defined manner and,moreover, a change in the direction of flow of the liquid when leavingthe guide plate is prevented.

In order to adjust the width of the liquid film in dependence on thesubstrates which are to be wetted, provision is preferably made for amechanism for opening and closing pre-determined nozzles, and inparticular, the outermost nozzles.

For the purposes of producing a homogeneous liquid film, an angle withinthe range of 90° to 94° is formed between the nozzles and the guideplate. Good process results can be obtained, in particular, in anangular range of between 90.5° and 93° or between 90.5° and 92°.

The device in accordance with the invention is particularly suitable foruse in the field of wafer and mask production wherein very finestructures have to be processed and wherein extremely homogeneousprocess conditions must prevail.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in more detail hereinafter with the aid of apreferred exemplary embodiment taken in conjunction with the drawings.Therein:

FIG. 1 shows a schematic plan view of a device for treating masks in theproduction of wafers which comprises a nozzle assembly in accordancewith the present invention;

FIG. 2 a schematic front view of a nozzle body in accordance with thepresent invention;

FIG. 3 a schematic sectional view through the nozzle body in accordancewith FIG. 2;

FIG. 4 a schematic side view of a nozzle assembly in accordance with thepresent invention;

FIG. 5 a schematic partial sectional view through a nozzle assembly inaccordance with the present invention;

FIG. 6 a schematic front view of a nozzle assembly in accordance withthe invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS

FIG. 1 shows a schematic plan view of a device 1 for treating masks 2used for the production of semiconductor wafers. The device 1 includes atreatment container 4 having a side wall 5 which is conically tapered atleast in an upper portion 7 thereof and thereby forms an upper, roundinput/output opening 8. The base of the treatment container 4 is formedby an appropriate base plate which is fixed together with the side wall5 to a mounting plate 10. The upper input/output opening 8 is adapted tobe closed by an appropriate cover which is not illustrated in detail. Aplurality of through holes 12 providing a feed passage for differenttreatment systems, in particular feed lines for different liquids, isprovided in the conical part 7 of the side wall 5.

A rotatable receiver or seating mechanism 15 is provided inside thetreatment container 4, said mechanism comprising four receiver orseating elements 17 in accordance with FIG. 1. The seating mechanism 15is rotatable by means of a shaft extending through the bottom wall ofthe container and a suitable drive. The seating mechanism 15 isdynamically balanced in such a manner as to make high numbers ofrevolutions possible.

Below the seating mechanism 15, there is provided a sealing bellows 19which seals the shaft of the seating mechanism 15 with respect to theprocessing environment. Apart from its sealing function, the bellows,which may be in the form of a blacksmiths bellows for example, alsoserves for displacing the seating mechanism perpendicularly relative tothe plane of the drawing of FIG. 1. Naturally, this function could alsobe provided by any other suitable device.

Furthermore, a nozzle assembly 22 in accordance with the invention canbe perceived in FIG. 1, this assembly being arranged partly above themask 2 in the illustration of FIG. 1.

The nozzle assembly 22 consists of an inlet line 24, a nozzle body 26and a deflector or guide plate 28 which is not visible in FIG. 1 but canbest be seen in FIG. 4.

The inlet line 24 incorporates a tubing section 30 which extendssubstantially perpendicularly relative to the plane of the drawing ofFIG. 1 and is connected to a swivelling mechanism in an appropriatemanner for the purposes of pivoting the inlet line 24 about a pivotalaxis extending perpendicularly to the plane of the drawing in thevicinity of the section 30. Furthermore, the inlet line 24 includes asection which forms an extension arm 32 that extends substantially inthe plane of the drawing in accordance with FIG. 1. The nozzle body 26is mounted on the free end of the extension arm 32 in an appropriatemanner. The nozzle body 26 is formed by a straight elongated body whichextends at an angle with respect to the main direction of extent of theextension arm 32. Due to the fact that the inlet line 24 is pivotal inthe vicinity of the section 30, the nozzle body 26 can be pivoted from aregion within which it is not arranged above the mask 2 into a regionwhere it is above the mask and is pivotal over the entire mask. Theangle between the main direction of extent of the extension arm 32 andthe nozzle body 26 thereby results in a larger pivotal range. Thisenables the mask 2 to be lifted out of the treatment container 4 in adirection perpendicular to the direction extending in the plane of thedrawing of FIG. 1. This is necessary so as to give an external handlingrobot access to the mask 2 in order to remove it from the seatingmechanism 15 or to deposit a new mask thereon.

Furthermore, the pivotal movement of the nozzle body 26 enables the mask2 to be wetted in its entirety as will be described in more detailhereinafter.

FIG. 2 shows a schematic front view of the nozzle body 26 without theguide plate 28 and FIG. 3 shows a schematic sectional view through thenozzle body 26, likewise without the guide plate 28 attached thereto. Ascan be perceived from FIGS. 2 and 3, a total of 20 nozzles 36 areprovided in the nozzle body 26, said nozzles being disposed in astraight line. The nozzles 36 are each formed by corresponding straightbores in the nozzle body 26. The nozzles 36 are connected to adistributor line 38 which extends perpendicularly relative to thenozzles 36 and is formed by a straight blind bore 40 in the nozzle body26. The blind bore 40 extends into the nozzle body 26 from the endthereof remote from the inlet line 24. The open end of the blind bore 40is closed by a suitable plug 42.

Alternatively, the bore 40 could also extend completely through thenozzle body 26 and the respective opposite openings could be closed inan appropriate manner. For example, each of the opposite ends could beclosed by a slider which enables a connection between the distributorline 38 and the outermost nozzles 36 to be blocked in order to therebygradually reduce the number of nozzles 36 supplied with the liquid. Sucha decrease in the number of operable nozzles can be effected from oneside in the case of the blind bore or from both sides in the case of athrough-bore in order to obtain a more symmetrical arrangement.

Furthermore, a supply line 44 is provided in the nozzle body 26, thisline being formed by an appropriate blind bore 46. Although this is notperceptible in FIG. 3, the supply line 44 is, in terms of height, belowthe distributor line 38. Moreover, the nozzles 36 are connected to thedistributor line at or in the proximity of the highest point thereof.Furthermore, in the case of a normal alignment of the nozzle body 26,the nozzles 36 rise with respect to the horizontal, i.e. they have aninlet end 50 which communicates with the distributor line 38 and lies ata lower level relative to the outlet end 51 thereof. Thesecharacteristics of the geometrical arrangement of the supply line 44,the distributor line 38 and the nozzles 36 are also basically apparentfrom the schematic side view in accordance with FIG. 4 or the schematicpartial sectional view in accordance with FIG. 5.

The supply line 44 is connected by suitable feeder lines 54 to thedistributor line 38. The feeder lines 54 are evenly spaced with respectto the length of the distributor line 38 and are arranged symmetricallywith respect to a centre plane in order to make the pressuredistribution within the distributor line 38 as uniform as possible.

Instead of providing the supply line 44 extending laterally into thenozzle body 26 in the form of a blind bore with a lateral end connector45, it is also possible to provide the nozzle body 26 with asubstantially central connector in order to produce a betterdistribution of pressure within the supply line 44 and consequentiallywithin the distributor line 38. Furthermore, the use of a centralconnection of the inlet line 24 to the nozzle body 26 would increase thepivotal radius.

FIGS. 4 and 5 respectively show a schematic side view of a nozzle body26 and a guide plate 28 attached thereto, and a schematic partialsectional view through the nozzle body 26 and the guide plate 28. FIG. 6shows a schematic front view of the guide plate 28 and the nozzle body26.

As can best be perceived from FIG. 4, the guide plate 28 comprises atrapezoidal base plate 60 whose longer side faces toward the nozzle body26. The longer side is partly provided with a layer 62 of hydrophobicmaterial, whereby the layer 62 extends beyond the lower end of the basebody 60 and ends in a sharp edge 64.

The base body 60 comprises a through-bore 65 which extendsperpendicularly relative to the main sides and has a semicircular recessfor accommodating a ball nut 66 at the end thereof remote from thenozzle body 26. A bolt 68 extends through the bore 65 in the nozzle body60 and a corresponding bore 69 in the nozzle body 26 and is screwed intothe ball nut 66. The guide plate 28 is held on the nozzle body 26thereby. The guide plate 28 is hereby pivotal about the ball nut 66 to asmall extent. The degree to which pivotal movement can occur isbasically limited by the play of the bolt 68 in the through-bore in thebase body 60. The degree of pivotal movement is adjusted by means of aset screw 70 within the nozzle body 26. Naturally, although only onefixing bolt 68 and one set screw 70 are illustrated in FIG. 4, aplurality of fixing bolts and/or set screws can be provided over thewhole width of the guide plate 28.

As can be seen in FIG. 4, the fixing bolts 68 and set screws 70 arelocated above the nozzles 36 and above the hydrophobic layer 62. Thehydrophobic layer 62 extends downwardly from the through-bore in thebase body 60, but naturally, it could also extend above thethrough-bore. A dove tail groove 72 for accommodating a round sealingelement 74 is provided in the nozzle body 26. The dove tail groove 72 isprovided in a surface of the nozzle body 26 facing towards the guideplate 28 and, in terms of height, is located between the nozzles 36 andthe bores for accommodating the fixing bolts 68. The round sealingelement accommodated in the dove tail groove 72 seals with respect tothe guide plate 28 and prevents the liquid flowing out of the nozzles 36under pressure from flowing upwardly.

Below the nozzles 36, the nozzle body 26 has a flat wall 76 whichextends substantially perpendicularly downwards and ends at a lower edge78. This flat wall together with the guide plate 28 and particularlywith the hydrophobic layer 62 forms a downwardly widening gap 80, as canbest be seen in FIG. 5. The gap 80 forms an acute angle α whichpreferably lies between 0.5° and 4° and can be varied by theabovementioned adjusting mechanism. Hereby, the angle can preferably liebetween 1° and 3° or between 1.5° and 2.5°. The widening gap enables ahomogeneous liquid film to be formed in an effective manner from theliquid issuing from the nozzles 36, as will be described in more detailhereinafter.

The lower edge 78 of the straight wall 76 of the nozzle body 26 endsabove the lower sharp edge 64 of the hydrophobic layer 62 in order toprevent the liquid film that was formed therebetween from runningunevenly off the lower edge 64.

FIG. 6 shows a schematic view of the guide plate 28 and a liquid film 84running off it. The nozzle body 26 is not perceptible in this viewbecause it basically lies behind the guide plate 28. The width of theguide plate 28 and the nozzle body located behind it is greater than thewidth of the mask which is to be wetted although the latter is notillustrated in FIG. 6. As can be seen from FIG. 6, the liquid film 84formed on the guide plate 28 extends over the entire width of the guideplate 28 and has a homogeneous central region 86 as well asinhomogeneous boundary regions 88, this being the result, inter alia, ofthe fact that each of the outer nozzles 36 in the nozzle body 26 onlyhas one neighbouring nozzle in each case. The width of the homogeneouscentral region 86 of the liquid film 84 corresponds to at least thewidth of the mask which is to be wetted in order to ensure homogeneouscoating thereof. This can be achieved by virtue of the guide plate 28having a greater width than the mask which is to be coated and by virtueof the spacing between the outer nozzles 36 in the nozzle body 26 beinggreater than the width of the mask. If, as in the device illustrated inFIG. 1, the nozzle assembly 22 is pivoted over the mask 2, the length ofthe homogeneous central region must naturally be such as to correspondto at least the maximum covering of the mask 2, this being achievable bymeans of an appropriate length of the guide plate and an appropriatespacing between the outer nozzles.

The employment of the nozzle assembly in accordance with the inventionwill be described in more detail hereinafter with the aid of theFigures.

Firstly, the nozzle assembly 22 is moved out of the range of verticalmovement of the seating mechanism 15. Subsequently, the seatingmechanism 15 is raised vertically. A mask requiring processing 2 isseated on the seating elements 17 of the seating mechanism 15 by a notillustrated handling robot. The seating mechanism 15 is again movedvertically downward so that, in terms of height, it is located under thenozzle assembly 22.

A treatment liquid, such as a developer liquid for example, isintroduced into the nozzle body 26 via the inlet line 24. Hereby, theliquid is introduced via the supply line 44. The liquid rises upwardlyin the supply line 44 and then flows via the feeder lines 54 into thedistributor line 38. The liquid thus rises against the force of gravitywhereby air cavities in the respective lines are avoided. From thedistributor line 38, the liquid enters the nozzles 36, whereby thenozzles 36 are filled from the bottom up due to the upward gradient ofthe nozzles 36. Again, air cavities in the liquid are thereby avoided.Moreover, air cavities are prevented by virtue of the fact that theliquid is introduced into the nozzle body 26 at high pressure. When theliquid issues from the outlet ends 51 of the nozzles 36, it impinges onthe guide plate 28, and in particular, the hydrophilic layer 62. Due tothe pressure, the liquid spreads laterally and downwardly along theguide plate 28. Upward propagation thereof is prevented by the seal 74.A homogeneous liquid film is thereby formed on the hydrophobic layer 62,this film then flowing off downwardly. The homogeneity of the formingliquid layer is assisted by the downwardly widening gap 80 which alsocontributes to a calming of the current flow.

When the downwardly flowing liquid film 84 has formed, the nozzleassembly 22 is pivoted by means of the not illustrated pivotal device insuch a manner that the nozzle body sweeps over the entire mask 2 at auniform speed. The downwardly flowing liquid film 84 thereby forms ahomogeneous liquid layer on the mask 2.

Prior to the sweep of the nozzle assembly over the mask 2, the distancebetween the lower edge 64 of the hydrophobic layer 62 and the top faceof the mask 2 is adjusted by means of the bellows 19. This distance canbe made very small in order to keep the mechanical force with which theliquid film 84 is applied to the surface of the mask very low. The speedof flow of the liquid in the nozzle assembly 22 and hence the speed offlow of the liquid film 84, as well as the speed of the pivotal movementare selected in such a manner that a liquid layer having a suitablelayer thickness is formed on the mask 2.

After the sweep of the nozzle assembly 22 over the mask 2, the flow ofliquid into the nozzle assembly 22 is switched off and the nozzleassembly 22 is pivoted back into its starting position, i.e. outside therange of vertical movement of the seating mechanism 15. Since the nozzleassembly 22 is filled against the force of gravity, there is no fear ofliquid flowing out inadvertently after the stream of liquid has beenswitched off so that the nozzle assembly 22 can be pivoted back safely.

Subsequently, the mask 2 is further processed in known manner. Finally,the mask 2 is removed from the device 1.

The invention has been described hereinabove with the aid of a preferredexemplary embodiment of the invention, without being limited to theconcretely illustrated exemplary embodiment. For example, the nozzleassembly in accordance with the invention is also suitable for thewetting of semiconductor wafers or any other types of substrates. Inparticular, the application of a wetting liquid in as force-free amanner as possible is also necessary for semiconductor wafers since thecomponents formed thereon which have dimensions in the nanometer rangecan easily be destroyed. Furthermore, the provision of a hydrophobiclayer 62 on the guide plate 28 is not absolutely necessarily.Rathermore, the guide plate 28 could be formed by a base body 60 alone.

The specification incorporates by reference the disclosure of Germanpriority document 10232984.2 filed Jul. 19, 2002 and PCT/EP2003/007494filed Jul. 10, 2003.

The present invention is, of course, in no way restricted to thespecific disclosure of the specification and drawings, but alsoencompasses any modifications within the scope of the appended claims.

1. A nozzle assembly for applying a liquid to a substrate, wherein thenozzle assembly comprises a nozzle body incorporating a plurality ofnozzles located substantially in a line and a substantially verticallyextending guide plate having a flat surface and a straight lower edgewherein the nozzles are directed towards the flat surface of the guideplate above the lower edge so that a liquid film forms on the guideplate and flows off over the lower edge, wherein a downwardly wideninggap is formed between the nozzle body and the guide plate, said wideninggap being formed by a flat surface of the nozzle body and the flatsurface of the guide plate which are arranged at an acute angle (α) ofbetween 0.5 and 4° relative to one another, and wherein the planes ofthe flat surfaces cross above the nozzles in the area of the nozzlebody.
 2. A nozzle assembly in accordance with claim 1, wherein the acuteangle (α) is adjustable.
 3. A nozzle assembly in accordance with claim1, wherein the acute angle (α) lies between 1° and 3°, and morepreferably between 1.5° and 2.5°.
 4. A nozzle assembly in accordancewith claim 1, wherein the flat surface of the guide plate extendsdownwardly over the entire flat surface of the nozzle body.
 5. A nozzleassembly in accordance with claim 1, wherein the guide plate is attacheddirectly to the nozzle body, or wherein the guide plate is attached tothe nozzle body above the nozzles.
 6. A nozzle assembly in accordancewith claim 1, wherein a seal is located above the nozzles between thenozzle body and the guide plate.
 7. A nozzle assembly in accordance withclaim 6, wherein a recess is provided in the nozzle body foraccommodating the seal.
 8. A nozzle assembly in accordance with claim 7,wherein the inlet ends of the nozzles flow into a common distributorline which has a substantially larger cross section than the respectivenozzles.
 9. A nozzle assembly in accordance with claim 8, wherein theinlet ends of the nozzles lie at or in the proximity of a highest pointof the distributor line.
 10. A nozzle assembly in accordance with claims8, wherein a supply line is located below the distributor line and isconnected by a plurality of feeder lines to the distributor line.
 11. Anozzle assembly in accordance with claim 10 wherein the feeder lines areevenly spaced over the entire length of the distributor line.
 12. Anozzle assembly in accordance with claim 6, wherein the seal has a roundcross section.
 13. A nozzle assembly in accordance with claim 1, whereinthe nozzles are formed by straight passages in the nozzle body andwhereby, in terms of height, an inlet end of the passage lies below anoutlet end.
 14. A nozzle assembly in accordance with claim 1, wherein atleast one surface of the guide plate directed toward the nozzlesconsists of a hydrophilic layer.
 15. A nozzle assembly in accordancewith claim 1, wherein a mechanism is provided for producing a relativemovement between the substrate (2) and the nozzle assembly.
 16. A nozzleassembly in accordance with claim 15, wherein the mechanism comprises aunit for moving the nozzle assembly substantially parallel to thesurface of the substrate, or a linear-movement unit for moving thesubstrate and/or the nozzle assembly.
 17. A nozzle assembly inaccordance with claim 16, wherein the nozzle body and the guide plateare attached to a pivotal arm.
 18. A nozzle assembly in accordance withclaim 1, wherein the guide plate is wider than the substrate.
 19. Anozzle assembly in accordance with claim 1, wherein the outermostnozzles along the line are spaced by a distance which is greater thanthe width of the substrate.
 20. A nozzle assembly in accordance withclaim 1, wherein a mechanism is provided for adjusting the spacingbetween the lower edge of the guide plate and the substrate.
 21. Anozzle assembly in accordance with claim 1, wherein the lower edge ofthe guide plate is a sharp edge.
 22. A nozzle assembly in accordancewith claim 1, wherein a mechanism is provided for opening and closingpre-determined nozzles.
 23. A nozzle assembly in accordance with claim22, wherein said mechanism is provided for opening and closing outermostones of the nozzles.
 24. A nozzle assembly in accordance with claim 1,wherein an angle within the range of 90° to 94°, and preferably between90.5° and 93° is formed between the nozzles and the guide plate and morepreferably between 90.5 and 92.